Purpose: As marijuana laws have become more permissive, survey data on adolescents in the United States have shown an increase in marijuana-specific risk factors, particularly in the proportion of youth who do not perceive marijuana use as harmf[...]

ENGLISH:
Background: Marijuana policies are rapidly evolving. In the United States, recreational use of marijuana is now legal in 4 states and medical marijuana is legal in 23 states. Research evaluating such policies has focused primarily on h[...]

OBJECTIVE: This study examined the association between age at alcohol use onset and adult alcohol misuse and dependence by testing the sensitive-period hypothesis that early adolescence (11-14) is a vulnerable period of development during which [...]

As of January 2016, 23 U.S. states and the District of Columbia have legalized medical or nonmedical cannabis, with more likely to follow. This dynamic policy context represents a substantial challenge for policy evaluation. Part I of this artic[...]